Diaphragm and wear shoe assembly for clutch or brake



June 4, 1963 K. E. KNx-:uss 3,092,231

DIAPI-IRAGM AND WEAR SHOE ASSEMBLY FOR CLUTCH OR BRAKE Filed June 29, 1961 INVENToR.

/KfA/A/f/*f/ AKA/asis United States Patent O 3,092,231 DIAPHRAGM AND WEAR SHOE ASSEMBLY FOR CLUTCH R BRAKE Kenneth E. Kneuss, Cleveland, Ohio, assignor to Fawlcli Corporation, Cleveland, Ohio, a corporation of Michlgan Filed June 29, 1961, Ser. No. 120,610 Claims. (Cl. 192107) This invention relates to an assembly of a hollow, fluid-distensible diaphragm, which has an annular inside circumferential wall of rubber-like material, and a plurality of circumferentially spaced wear shoes mounted on this diaphragm Wall for movement radially into and out of engagement with `a clutch lor brake drum as the diaphragm is inflated and deated.

The wear shoes in the present assembly have individual slip-'on connections at lthe inside circumferential wall of the diaphragm, so that they may be replaced readily individually. In `accordance with the present invention the diaphragm has a novel arrangement for preventing the Wear shoes from becoming loose or completely detached from the diaphragm as a result of the repeated operation of the clutch or brake.

It is an object of this invention to provide a novel and improved diaphragm and wear shoe assembly for a constricting clutch or brake.

It isv also an object of this invention to provide such an assembly in which the Wear shoes have a more secure slip-on attachment to the diaphragm.

Another object of this invention is to provide such an assembly in which the diaphragm has improved dimensional stability where the wear shoes are attached.

Further objects and advantages of this invention will be apparent from the following detailed description of a presently-preferred embodiment thereof, which is illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is yan axial section, with parts broken away, of a diaphragm `and wear shoe assembly embodying the present invention;

FIGURE 2 is a partial end elevational view of the FIGURE 1 assembly;

FIGURE 3 is an enlarged fragmentary section showing the slip-on `attachment of a wear shoe to the diaphragm; and

FIGURE 4 is la plan view of one of the reinforcing plates embedded in the diaphragm.

Referring first to FIGURE l, the usual annular clutch or brake drum is surrounded by a hollow, annular, fluid-distensible diaphragm or torque bag 11. The diaphragm is securely attached to the inside of `a metal ring 12. Either the drum 10 or the ring 12 is rotatable with respect to the other. The diaphragm 11, when inflated, provides a clutching engagement Ior coupling between these members. An inlet-outlet fitting 13 supported by the ring 12 provides for the flow of suitable iluid, such as air or hydraulic liquid, into and out of the diaphragm.

The diaphragm or ltorque bag 11 is made up of an outer hollow annulus A11a, which at its outer circumference is vulcanized to the inside of ring`12, and an inner tube 11b. Preferably, both the inner :and outer members of the diaphragm are made of cord-reinforced, vulcanized soft rubber or other rubber-like material having suitable characteristics of deformability and resiliency. As shown in FIGURE 1, the iluid inlet-outlet iitting 13 communicates with the interior of the inner tube 11b. When fluid under pressure is introduced through this fitting into the inner tube, the diaphragm is distended radially inwardly toward the drum 10.

As shown in FIGURE 1, the outside member 11a of the `diaphragm has an inner circumferential Wall 14 which is relatively thick radially `and is substantially thicker axially. As best seen in FIGURE 2, this inside wall of the diaphragm is formed with a series of circumferentially spaced, axially extending, wear shoe recesses 15. Each of these recesses is substantially T-shaped, viewed axially, and each is open at both axial ends of the diaphragm.

Between each successive pair of such recesses 15 the inside wall of the diaphragm presen-ts an integral, radially inwardly protruding, arcuate segment 16 which has circumferentially projecting, wear shoe interlock anges 16a and 16b at its `opposite circumferential ends. Each of these flanges presents a shoulder, 16a br 1Gb', which faces radially outward. As best seen in FIGURE l, the axial length of each segment 16 is somewhat shorter than that of the remainder of the diaphragm. Each ange 16a and 16b extends the full axial length of the corresponding segment 16.

The space betweenthe confronting end faces of the interlock ilanges 16a land 16b on each pair lof neighboring segments 16 defines the stem, or narrow portion, of the T of the recess 15' between them. The head, or wide portion, of the T is Iat .the radial space between the radially youtwardly-facing shoulders 16a and lob on these interlock anges 16a and 16b and the inside circumferential surface 14a of the diaphragm Wall 14.

The lassembly also includes a' plurality of wear shoes 17 detachably mounted individually on the diaphragm segments 16. Each of these wear shoes comprises an arcuate block 1S of friction material and an arcuate sheet metal base plate 19. Each base plate has hookshaped opposite ends 19a and 1gb which snugly engage the respective interlock anges 16a and 1Gb on the opposite ends of the corresponding segment 16 of the diaphragm. As best seen in FIGURE 2, each of these hookshaped ends extends radially outward `snugly across the end face of the respective interlock flange 16a or 1Gb and then circumferentially snugly across its radially outwardly-facing shoulder 16a or 1Gb. Each friction block '1S is secured, such as by vulcanized adhesion, to the larcuate radially inward face of the corresponding base plate 19. The latter has a curvature conforming closely to the arcuate curvature 'of the radially inside face of the respective diaphragm segment 16.

As shown in FIGURE l, each wear shoe base plate 19 is formed with an integral, radially 4outwardly projecting, rounded protrusion 30 which is received snugly in a complementary recess 31 in the radially inward face, of the corresponding diaphragm segment 16. This is to prevent the -wear shoe from accidentally sliding endwise (axially). after it has been assembled onto the diaphragm.

4In accordance with the present invention a rigid reinforcing plate 120, preferably of steel, is embedded in and completely covered by the rubber-like matei'ialof each vdiaphragm segments 16 by vulcanized adhesion.

. 3 The plates are secured in the As shown in FIGURE 2, each of these reinforcing plates has an arcuate curvature corresponding to the curvature of the diaphragm where it is located. Each reinforcing plate extends from the interlock flange `16a at one end of the respective diaphragm segment 16 to the interlock flange 16b at the opposite end. Each plate 20 is positioned just a slight distance radially inward from the radial positions of the respective shoulders 16a' and 16b' on the corresponding diaphragm segment 16, as best seen in FIG- URE 3.

As shown in FIGURE 4, each plate 20 is formed with a plurality of holes 21. The plates are positioned in the mold before the diaphragm is molded. While the diaphragm is-being molded its rubber-like material fills the holes 21 to enhance the connection between the diaphragm and each reinforcing plate.

=Each wear shoe may be mounted on the diaphragm by sliding i-t axially across the respective diaphragm segment 16, with its hook-shaped ends 19a and 19b engaging the diaphragm segment 16.

respective interlock flanges 16a and 16-b on the diaphragm segment. 'I'he turned-in end extremities of the wear shoe base plates engage behind the shoulders y16a' and A16b', as shown in FIGURES 2 and 3.

It has been found that the provision of the reinforcing plates 20, `as described, greatly improves the security and stability of the interlock between the diaphragm and the wear shoes. Y

In the absence of these plates, when the diaphragm is intlated the wear shoes 17 move radially inward substantially immediately. However, the diaphragm segments 16 do not move radially inward immediately, so that for a visually observable interval there is a radial gap between the radially inside face of each diaphragm segment 16 and the base plate -19 of the corresponding wear shoe. Following this, the diaphragm segments 16 move inwardly and, at the same time, each segment 16 spreads circumferentially, exerting a very great endwise pressure against the hooked ends 19a and .19b of the wear shoe base plate. This circumferential cold tlowof the rubber, under the inuence of the inflation pressure, tends to spread `apart the Y opposite hooked ends of the wear shoe base plate. In

some instances, this may be sutiicient to abruptly force the wear shoe oif the diaphragm. In other instances it permanently deforms the hooked ends of the wear shoe,

so that when the ination pressureV is released and the diaphragm returns to its initial condition the wear shoe no longer has a snug interlock with the diaphragm.

It has been found that the reinforcing plates 20 substantially eliminate this disadvantageous cold ti'ow of the diaphragm segments 16 when the diaphragm is inflated. Instead, each rdiaphragm segment 16 retains substantially the same size `and shape, regardless of whether the diaphragm is inflated. Thereforethe snug interlock between the diaphragm Yand each wear shoe is maintained over a substantially indefinite period of time. Apparently, the presence of each' plate 20 at a location just radially inward from the wear shoe interlock portions of the diaphragm prevents 'any substantial cold flow of the rubberlike diaphragm material from taking place in the portion of each segment 16 between the embedded reinforcing plate' 20 and the radially inward face of the diaphragm segment. I'I'he cold ow can occur only in some other'por-r tion of the diaphragm, where its effects are of no consequence as far as the -wear shoe attachments are co-ncerned.

Another :observable effect is that the diaphragm segments 16 move radially inward in unison with the we-ar shoes substantially immediately when the diaphragm is inflated. The previously-noted tendency for a radial gap to occur between the wear shoe and the diaphragm is substa-ntially completely eliminated.

4 segments 16, Ias formed in the mold, are more exact than was possible heretofore. This makes it easier to provide a more accurate linitial snug lit: between these diaphragm segments Iand the wear shoes.

While a presently-preferred embodiment of the invention has been shown in the accompanying drawing and described in detail herein, it is to be understood that various modifications, omissions and renements which depart from the disclosed embodiment may be adopted without departing from the spirit and scope 'of this invention. For example, the reinforcing plates 20 could differ in size, shape or number from the particular arrangement shown. Also, each reinforcing plate 20 could be located closer to the radially inward face of the respective diaphragm segment y16 than shown. In any such alternative arrangement, as well -as in the preferred arrangement shown in the drawing, the thickness of each diaphragm segment 16 radially inward from the reinforcement 20 to the radially Vinward face of the diaphragm segment is small enough to prevent any substantial amount of cold flow of the rubber-like material there which would tend to dislodge the respective wear shoe from the diaphragm segment.

What is claimed is:

l. A diaphragm and wear shoe assembly comprising an annular hollow uid-distensible diaphragm having an annular inside circumferential wall of rubber-like material, said inside wall having la plurality of circumferenti'ally spaced segments at its radially inward side, each of said segments terminating at its opposite ends in circumferentially protruding interlock flanges which present radially outwardly facing shoulders, la plurality of rigid reinforcing plates embedded in said segments and respectively extending circumferentially from one interlock flange on the respective segment to the interlock ange on the opposite end thereof, anda plurality of wear shoes mounted on said segments yat the radially inward side of the latter, each of said wear shoes having hooked opposite ends which snugly engage said shoulders yonthe respective segments.

2. A diaphragm and wear shoe assembly comprising Yan annular hollow uid-distensible diaphragm'having an annular inside circumferential wall of rubber-like material, said wall having a plurality of circumferentially spaced integral segments yof rubber-like material which project radially inwardly, each of said segments terminating at each circumferential end thereof in a circumferentially protruding interlock ange which presents `a radially outwardly, facing shoulder, the adjacent ends of neighboring segments being separated by recesses which are T-shaped axially lof the diaphragm and which are open at the radially inward side of the segments, a plurality of arcuate rigid metal reinforcing plates embedded in 4and bonded to said diaphragm Wall segments, each `of said plates lying just radially inward from said shoulders and extending from the shoulder atv-one end of the respective segment to the shoulder at the opposite end thereof,

and -a plurality of Vwear shoes extending snugly across Y `an annular hollow uid-distensible diaphragm having an annular inside circumferential wall of rubber-like material, said wall having Va plurality of circumferentially spaced segments at its radially inward side, anda plurality of wear shoes detachably interlocked with said segments and extending `across the radially inward side of the latter, the improvement which comprises a pluralityV of rigid reinforcements embedded in and bonded to said segments, each of said reinforcements extending circumferentially in the respective segment sufciently close to Ithe radially inward side of the latter to substantially prevent cold ow in a circumferential direction of the rubberlike material of said segment thereat.

5. In a diaphragm `and Wear shoe assembly which includes an annular hollow fluid-distensible diaphragm of rubber-like material having a plurality of circumferentially spaced segments at its radially inward side, said segments terminating at each circumferential end in a circumferentially protruding interlock flange, and a plurality of wear shoes extending across the radially inward faces of the respective segments and having hooked ends engaging said interlock anges, the improvement which comprises a plurality of rigid reinforcement plates embedded in and bonded to said segments, each of said rein- References Cited in the le of this patent UNITED STATES PATENTS 1,330,756 Brown Feb. l0, 1920 1,420,979 Ehlich June 27, 1922 2,630,198 Kraft Mar. 3, 1953 2,662,625 Fawick Dec. 15, 1953 2,723,015 Wellauer Nov. 8, 1955 2,897,924 Fawick Aug. 4, 1959 

1. A DIAPHRAGM AND WEAR SHOE ASSEMBLY COMPRISING AN ANNULAR HOLLOW FLUID-DISTENSIBLE DIAPHRAGM HAVING AN ANNULAR INSIDE CIRCUMFERENTIAL WALL OF RUBBER-LIKE MATERIAL, SAID INSIDE WALL HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED SEGMENTS AT ITS RADIALLY INWARD SIDE, EACH OF SAID SEGMENTS TERMINATING AT ITS OPPOSITE ENDS IN CIRCUMFERENTIALLY PROTRUDING INTERLOCK FLANGES WHICH PRESENT RADIALLY OUTWARDLY FACING SHOULDERS, A PLURALITY OF RIGID REINFORCING PLATES EMBEDDED IN SAID SEGMENTS AND RESPECTIVELY EXTENDING CIRCUMFERENTIALLY FROM ONE INTERLOCK FLANGE ON THE RESPECTIVE SEGEMENT TO THE INTERLOCK FLANGE ON THE OPPOSITE END THEREOF, AND A PLURALITY OF WEAR SHOES MOUNTED ON SAID SEGMENTS AT THE RADIALLY INWARD SIDE OF THE LATTER, EACH OF SAID WEAR SHOES HAVING HOOKED OPPOSITE ENDS WHICH SNUGLY ENGAGE SAID SHOULDERS ON THE RESPECTIVE SEGMENTS. 